Optical properties of xanthene and coumarine dyes incorporated into a swelling clay were studid. Preparation of the dye-clay composites were carried out as follows ; a swelling clay was added thorughly mixed into various solvents containing the corresponding quantity of dye. After about week, The resulting composites were quickly recovered by filtration and washed several times with solvent, than dried overight at 100^ﾟ in air.The TG-DAT and the X-ray distraction data revealed that intercalted dye moleculres were immobilized and thermally stabilized over thleir melting temperatures. Also, the basal spacings of the clay were expanded up to the molecular size of dyes with slingt distortion of the layer structure on increasing the dye content.All the dominant fluorescences were observed, which were identified as the pi*-pi transition related to mesomeric structure of dye chromophore. Its quantum efficiency is briefly discussed in connection with concentration quenching phenomena. As the quantity of intercalated coumarine 1 increased, a pronunced stepwise was observed in basal spacings from 13.0 A to 18.5 A. Such a geometrical change of the flat-shaped coumarine chromophore significantly influenced the fluorescence properties. Also, the red shift of the emission maximum was elucidated by the charge stability of N atoms in the coumarine chromophore.When DMF (N, N-Dimethy Formamide) was used as solvent, tow fluorescence peaks were observed near 570 nm and 450 nm in the pyronine Y - montmorillonite system. This implied that the xanthene chromophore was partially decomposed to some coumarine-like structure by virtue of Na^+ ion incorp olated. DMF was also available fo intercalating Comarine 4 into tetrasilicic mica. It could be seen that the dye was readily solvated by DMF in the form of anionic struture. Its fluorescence spectra implied that an exciplex should be formed by the interaction between H^+ and 0^- ion of coumarine chromophore.